Coffee Consumption and the Risk of Thyroid Cancer: A Systematic Review and Meta-Analysis

Abstract

An inverse association has been reported between coffee consumption and the risk of several cancers. However, the association between coffee and thyroid cancer is controversial. Thus, this study aimed to evaluate the association between coffee consumption and the risk of thyroid cancer through a systematic review and meta-analysis. Published studies were examined from PubMed, Embase, Cochrane Central, and the reference lists of the retrieved articles. The summary odds ratio (OR) for the association between coffee consumption was categorized as highest versus lowest consumption, and thyroid cancer risk was calculated using a fixed effects model. Subgroup analyses by study design, geographic location, source of controls, and adjusted variables were performed. A total of 1039 thyroid cancer cases and 220,816 controls were identified from five case-control studies and two cohort studies. The summary OR for the association between coffee consumption and thyroid cancer risk was 0.88 (95% confidence interval (CI) = 0.71–1.07). There was no significant heterogeneity among the study results (I² = 0%, p = 0.79). However, the beneficial effect of coffee consumption on thyroid cancer was found only in hospital-based case-control studies (OR= 0.59, 95% CI= 0.37–0.93). There was no significant association between coffee consumption and thyroid cancer risk according to our meta-analysis results. These findings should be interpreted with caution because of potential biases and confounding variables. Further prospective studies with a larger number of cases are encouraged to confirm these results.

Endocrine Effects of Coffee Consumption

“…A total of 24 studies about thyroid cancer and coffee were found, out of which a total of 10 studies were included after the exclusion of duplications (n=8) and 'not suitable' (n=14) articles. As documented in Table 3, no association between coffee consumption and thyroid cancer could be extracted from the population-based cohort studies (54)(55)(56) and meta-analyses of cohort and case-control studies (57,58). While a few case-control studies reported contradictory results.…”

“…Only two studies have explored the effect of caffeinated or decaffeinated coffee consumption on thyroid cancer (TC) separately. The first one was a case-control study from German and detected that drinking decaffeinated coffee was associated with an increased risk of TC, whereas drinking caffeinated coffee had a preventive effect on thyroid cancer (57,61). The second one was a prospective cohort study from the USA with 167,720 non-white and white participants with 15.3 years follow-up period.…”

Coffee and tea drinking in relation to the risk of differentiated thyroid carcinoma: results from the European Prospective Investigation into Cancer and Nutrition (EPIC) study

“…Only few risk factors have been well-established for TC, such as history of having a benign thyroid tumor, exposure to ionizing radiation in childhood, and body fatness [4,5]. Dietary factors, such as nutrients and components (e.g., energy, polyunsaturated fatty acids, alcohol, and flavonoids) [6–8] and foods (e.g., fish, fruits and vegetables, coffee and tea) [9–12], have been suggested to play a role in TC etiology, although until now epidemiological evidence is still very limited and inconclusive [4].…”

Enzyme-Supported Immunotherapy: Case Study and Possible Generalizations

“…[1]. In a rat model, co-promoting effects of high doses of caffeine in thyroid carcinogenesis have been described [16], while the role of caffeine in human thyroid carcinogenesis remains controversial [17].…”